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J. N/DENNISSON.

Fire Engine.

Patented July 13, 1858.

UNITED STATES PATENT OFFICE.

JNO. N. DENNISSON, OE NEWARK, NEW JERSEY.

FORCE-PUMP FOR FIRE-EN GIN ES.

Specification of Letters Patent No. 20,867, dated July 13, 1858.

To all whom it may concern:

Be it known that I, JOHN N. DENNISSON, of the city of Newark, in the county of Essex, New Jersey, have invented certain Improvements in F ire-Engines, which I have described in the following specification and illustrated in the accompanying drawings with sufiicient perspicuity to enable others skilled in the business to make and use the same.

The nature of my invention consists in giving greater efficiency to the engine by increasing its capacity near the end of the stroke of the arms.

In the drawings Figure l is a perspective view of a fire engine with some parts removed to show, a mode of producing the desired result. Part of one cylinder is shown in section to make it plain. Fig. 2 is a sec tional view of the cylinder and double piston. Fig. 3 is a view in section of another manner of producing the same result as Fig. l.

The same letters refer to the same parts in each view.

A is the pump cylinder; B the main piston. C is an additional ring piston nicely fitted to and operating in the enlarged end of the cylinder A.

e, e, e, e are spiral springs under the ring piston C.

f is the bed plate; 9 the valve; h a port and 0 an air barrel.

When in use the under side of the piston B comes in contact with and forces down the ring piston C thus increasing the capacity of the engine just the difference of the additional area of the enlarged part of the cylinder in which the ring piston works. The spiral springs return the ring piston to its place when the main piston is withdrawn. The same result is produced also by the addition of a small cylinder by the side of the main cylinder, with a spring piston and a piston rod so placed that the arm of the engine when near the end of the stroke shall strike upon the top r, of the piston rod and so force an additional quantity of water in and through the main cylinder A, as shown in Fig. 3.

All persons familiar with the operation of fire engines are aware of the force with which the arms come down upon the box at the end of each stroke; the noise can often be heard at quite a distance. This evidently manifests a waste of effective force which it is our object to bring into available use. Springs have been placed on the edge of the boxes to gather the momentum and re turn the arm with more case, but this adds nothing to the effective force upon the water. There has ever been a waste of power which we now propose to prevent and make the power efficient.

As it is near the end of the stroke that the firemen are in the best position for the exertion of power, and being just at the place where all the possible momentum is gained from their exertions, it is found in practice to be a great improvement beyond all other engines to increase the capacity of the engine at just the spot and make the power operate effectually upon the water just at the time when the exertion is made with the most ease to the firemen; this our improvement does most efliciently; water is thrown from ten to twenty feet farther than by any other engine with the same area in a straight bore or in a single straight cylinder.

What I claim as my improvement and desire to secure by Letters Patent is Increasing the capacity of the pumps of fire engines near the end of the stroke by the expedients described or their equivalents.

J. N. DENNISSON.

Witnesses:

WV. M. GooDINe, D. D. TINGLEY. 

